Experimental Chemistry Starting Check · G2 Science Chemistry

Diagnose, practise and repair the required G2 Experimental Chemistry capability groups without treating an online selected response as evidence of hands-on practical mastery.

SEC G2 Science Chemistry component 2027

This check shows what to work on next. It and the practice after it don’t count towards mastery; only a later progress check can count towards your course progress.

Check what I know

Start here to see which parts you already know.

About 8 minutes

Answer 10 short questions. It shows what to work on next and doesn't count towards mastery.

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This check needs JavaScript to record answers. The reviewed questions are listed below for study.

Which titration apparatus pairing is correct?

Measuring cylinder—indicator; filter funnel—titrant
Conical flask—fixed calibrated aliquot; beaker—variable measured titrant
Volumetric pipette—fixed aliquot; burette—variable measured titrant
Volumetric pipette—variable titrant; burette—fixed aliquot

Which setup can record decreasing mass while a gas escapes from a reaction flask?

Place the flask on a digital balance and record mass at timed intervals
Collect the gas in a syringe and record its volume only.
Weigh the reactants once before mixing, without further readings.
Seal the flask with an airtight bung and record its mass.

Three dissolving times at 40 °C are 31 s, 30 s and 72 s. What is the best response?

Check the method and repeat the 40 °C trial before deciding how to treat 72 s
Average all three immediately without comment
Discard 31 s and 30 s because there are two of them
Change 72 s to 32 s because it looks too large

Gas escapes before the bung is fitted, giving volumes that are too low. Which improvement targets this error?

Keep the reactants separate in the flask, fit the bung and gas syringe, then tip to mix.
Use a larger reaction flask but fit the bung after mixing.
Repeat with the bung fitted after the same delay
Start the stopwatch when the bung is fitted, after mixing.

A mixture contains insoluble sand in sodium chloride solution. To recover the sand and salt separately, what should be done first?

Filter and keep the paper as the dissolved salt fraction.
Distil and collect the condensed water as the sand fraction.
Evaporate to dryness and keep the sand and salt together.
Filter and keep the sand residue and salt-solution filtrate separately.

Two miscible liquids have close boiling points and can be separated by distillation. Which setup improves their separation through repeated vaporisation and condensation?

Fractional distillation.
A separating funnel.
Filtration.
Simple distillation without a fractionating column.

One sample produces two separate spots on a paper chromatogram. Assume neither the paper nor the solvent reacts with the sample. What does this show?

The sample is one pure substance because both spots moved.
The sample contains exactly two substances, with no others possible.
The paper has changed one substance into two new substances.
The sample contains at least two substances separated under these conditions.

Before choosing evaporation, crystallisation or distillation for a solution, which information is needed?

The required product, its heat stability and how its solubility changes with temperature.
The required product and the colour of the heating apparatus.
The solvent volume and the pore size of filter paper, without identifying the product.
The highest temperature available, without considering the solute.

An unknown dye and a known dye produce spots at the same height. Which setup makes this height comparison meaningful?

Different start lines on the same sheet, without measuring their positions.
Different solvents and papers, each run for a different distance.
The same sheet and solvent run, with both samples on the same start line.
Different chromatograms compared only because their spots have the same colour.

At constant pressure matching the references, sample P boils sharply at the reference temperature of its proposed substance. Sample Q boils over a range. Which inference is best supported?

Q is more likely to be pure because it has a range of boiling temperatures.
Both samples have their proposed identities because each reaches boiling.
P is likely impure because its boiling temperature stays fixed.
P’s result supports its proposed identity and purity; Q’s range suggests a mixture.

Practise

Work through questions with marking and feedback as you learn.

About 10 minutes

Questions are picked at random each time you start. You'll see the answer after each question. It's for practice only and doesn't count towards mastery.

Recent attempts

History is stored only in this browser.

No completed attempts are saved yet.

This check needs JavaScript to record answers. The reviewed questions are listed below for study.

Gas escapes before the bung is fitted, giving volumes that are too low. Which improvement targets this error?

Keep the reactants separate in the flask, fit the bung and gas syringe, then tip to mix.
Use a larger reaction flask but fit the bung after mixing.
Repeat with the bung fitted after the same delay
Start the stopwatch when the bung is fitted, after mixing.

Three dissolving times at 40 °C are 31 s, 30 s and 72 s. What is the best response?

Check the method and repeat the 40 °C trial before deciding how to treat 72 s
Average all three immediately without comment
Discard 31 s and 30 s because there are two of them
Change 72 s to 32 s because it looks too large

Which titration apparatus pairing is correct?

Measuring cylinder—indicator; filter funnel—titrant
Conical flask—fixed calibrated aliquot; beaker—variable measured titrant
Volumetric pipette—fixed aliquot; burette—variable measured titrant
Volumetric pipette—variable titrant; burette—fixed aliquot

Which setup can record decreasing mass while a gas escapes from a reaction flask?

Place the flask on a digital balance and record mass at timed intervals
Collect the gas in a syringe and record its volume only.
Weigh the reactants once before mixing, without further readings.
Seal the flask with an airtight bung and record its mass.

Before choosing evaporation, crystallisation or distillation for a solution, which information is needed?

The required product, its heat stability and how its solubility changes with temperature.
The required product and the colour of the heating apparatus.
The solvent volume and the pore size of filter paper, without identifying the product.
The highest temperature available, without considering the solute.

A sample is labelled solid X. Pure X has a reference melting point of 80 °C. Which measured melting behaviour best supports the sample being pure X?

A sharp melting point near 80 °C.
A broad melting range from 68 °C to 78 °C.
A sharp melting point near 60 °C.
A broad melting range from 50 °C to 90 °C.

A food colouring produces three separate spots on a paper chromatogram. Assume the colouring does not react with the paper or solvent. What can be concluded?

It contains at least three substances separated under these conditions.
It contains exactly three substances, with no additional components possible.
It is one pure substance because all spots are on the same paper.
It is one substance that the solvent changed into three new substances.

Practise after feedback

After a check, practise the skills it showed you need to work on.

About 10 minutes

Questions are picked at random each time you start. You'll see the answer after each question. It's for practice only and doesn't count towards mastery.

Recent attempts

History is stored only in this browser.

No completed attempts are saved yet.

Experimental Chemistry Starting Check · G2 Science Chemistry

Check what I know

Starting check complete

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Practise

Practice complete

Your answers

Practise after feedback

Practice complete

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